Motor function in early onset schizophrenia-A 2-year follow-up study

Motor symptoms primarily assessed by clinical rating are documented across the schizophrenia spectrum, but no studies have examined the longitudinal course of these symptoms in adolescents using tests that control for the natural maturational process. The aim is therefore to compare fine and gross motor function using age-adjusted tests in adolescents with schizophrenia and controls across a 2-year period, and examine if clinical correlates contribute to changes in motor function in adolescents with schizophrenia.

Motor function assessed by two age-adjusted tests was compared in 25 adolescents with schizophrenia and age- and sex-matched controls over a 2-year period using t-tests, Cohen's D and χ² tests. Linear mixed models with a random intercept at patient level were used to assess changes between baseline and follow-up. The latter approach was adopted to assess the association between changes and potential predictors as age, sex, complications during labour/delivery, childhood motor function, symptoms severity, executive function and antipsychotics.

All measures of motor function but one significantly differentiated adolescents with schizophrenia from controls with large effect sizes at 2-year follow-up. The overall scores did not change during follow-up, whereas two resembling motor areas of the tests significantly improved in adolescents with schizophrenia. The severity of schizophrenia, sex and IQ revealed association with the changes.

The finding of both stability and improvements from diagnosis to follow-up in adolescents with schizophrenia and the differences between adolescents with and without schizophrenia argue in favour of the neurodevelopment hypothesis and highlights the need for assessing motor function.